Artificial hand



Och 1950 A. F. SYVERUD EIAL. 2,528,323

ARTIFICIAL HAND Filed Dec. 8, 1947 s Sheets-Sheet 1 INVENTORS ANNAR F, SYVERUD BERTIL Go PETERSON O t. 31, 1950 A. F. SYVERUD ETAL 2,528,322

' ARTIFICIAL HAND Filed Dec. 8, 1947 s Sheets-Sheet 2 22 7 72 1 -1 37 l f F 73 I. -3 INVENTORSV 76 I H ANNAR E SYVERUD 77 67 ERT1L PETERSON ATTO R E 1950 I A. F. SYVERUD ETAL 2,528,322

ARTIFICIAL HAND Filed Dec. 8, 1947 3 Sheets-Sheet 3 \NVENTO'RS I ANNAR F; SYVERUD BE RTIL G. PETERSON ATTO RN E Y Patented Oct. 31, 1956 An'nar' Syverud andBertilG. Peterson,

.Minneapkilis,

Application December 8, 1947,"SerialN0. 790,266

13 Claims. (ore-12 1. The present invention has relation to .an artificial hand. This-application isa continuation in part of our pending application Serial No. 640,814, for Artific'ial I-Iand, filed January 12, 1946, and presents features and characteristics of construction which are improvements over the disclosure .of said application.

'An object of the invention is to provide an artificialhand which will include novel and improved "mechanism adapted to be acted to cause a thumb and fingers of the artificiaL'hand to be moved from open to partially closed or completely closed position and from closed or partially closedto open position and a novel and'improved construction and arrangement adapted to prevent the thumb and fingers of the artificial hand from being moved toward open position from closed or partially closed position when this -is intended.

A further object is to provide a new and improved artificial hand which will include a thumb and-finger normally in open condition, actuating '{means for' sele'ctivcly causing said thumb and finger to be moved from open to partially or completelvolosedcondition and from closed or partially closedto open condition, and a cons truction and arrangement under the control of 'saiid'actuating means for selectively locking said {thumb and fingers in closed or partially closed condition and releasing the thumb and fingers to be movable to open condition by said actuating mea And a further object is to provide a new and improved artificial hand which will include resilient means adapted to normally maintain a thumb and fingers of said artificial hand in open condition, mechanism adapted to be actuated against the potential of said resilient means to cause said thumb and fingers to be moved from open to partially or completely closed condition,

and devices adapted to be actuated in response to a manipulation of the mechanism causing said thumb and fingers to be moved from open to partially or completely closed condition to cause the'thumb and fingers to be positively locked in partially or completely closed condition to cause the thumb and fingers to be released thus to permit said resilient means to move said thumb and fingers to open condition.

2 With the above objects in View, as well as others which willappear as the specification proceeds; the invention comprises the construction, arrangement and combination of parts as now to'be fully described and as hereinafter to be specifically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in a limiting sense, changes in details of construction and arrangement of parts being permissible as long as within the spirit of the invention and the scope of the claims which follow.

In the accompanying drawings forming a part of this specification,

Fig. l is a perspective view of an artificial hand made according'to the invention;

Fig. 2 is a detail sectional View, taken substantially on line 2- -2 in Fig. 3, showing the thumb and'fingers of the artificial hand as when in a closed condition;

Fig. 3 is a fragmentary top plan View of the artificial hand, a cover for the body member of said-artificial hand being removed; Fig. 4 is a detail sectional view, taken on lin 1-4 in Fig.5, disclosing-operative elements of the artificial hand situated relative to each other substantially as in Fig. 2;

Fig. 5 is a top plan view of the operative elements shown in Fig. 4;

Fig. 6 is a detail sectional view, taken as on line 66 in Fig. 4;

Figs. 7, 8 and 9 are views, partially in section and partially in elevation, disclosing the operative elements shown in'Figs. 4 and 5 in several of the different positions said operative elements assume during practical operation of the artificial hand; and t Fig. 10 is a detail sectional view, taken on line HJI0 in Fig. 9.

A body member of the artificial hand, made in simulation of the metacarpus of a human hand, is denoted'l5, a'thum'b upon said body portion is represented H5, and fingers upon the body member are indicated I1. Said body member l5 houses a chamber l8, and a removable cover for said chamber is designated l9. A shank 20 is for attachment ofthe artificial hand to a member retained upon the armor shoulder of a human being.

The thumb I6 is pivotally supported, as at 2|, upon the body member [5 for swinging movement in a plane passed perpendicularly through the thickness of said body membenand an interior end portion of said thumb l6 lies within the chamber 18. A'link 22, within the chamber I8 and for a purpose to be made plain, has its forward end pivotally secured, as at 23, to an upwardly and rearwardly extending piece 24 rigid with the thumb I6. Resilient cushioning material on said thumb I6 is represented 25.

The fingers ll are rigidly connected to each other and are pivotally supported, as at 26, upon the body member for swinging movement in a plane passed perpendicularly through the thickness of said body member, toward and away from said thumb l6. An interior end portion of a unit constituting said fingers lies within the chamber I8. A link 21, within said chamber and for a purpose to be set forth, has its forward end pivotally secured, as at 28, to a rearward portion of the unit constituting the fingers H at a location spaced downwardly from the pivotal support 26 for said unit. As disclosed, the forward end portion of the link 2? is freely situated on a concavity in a rearward, lower portion of said unit constituting said fingers Resilient cushioning material on said fingers i1 is indicated 29.

Resilient means for normally maintaining the thumb l6 and the fingers H in open position includes a pushrod 36 within the chamber l8 having its forward end pivotally supported, as at 3|, upon a portion of the unit constituting the fingers H at a location spaced downwardly from said pivotal support 26, The pushrod 36 extends rearwardly into a longitudinally extending well 32 in the body member i5. A compression coil spring 33, upon the pushrod 36, has one of its ends engaged against a transverse wall of the body member l and its other end engaged against a collar 34 fixed on a forward portion of said pushrod 30. The construction and arrangement will be such that the compression coil spring 33 will normally urge the fingers l to their open hand position.

Mechanism adapted to be actuated against the potential of the compression-coil spring 33, to cause the thumb l6 and the fingers H to be moved from open to partially or completely closed condition, includes an actuating lever 35 and an actuated lever 36 both situated in the chamber 8 and having their lower end portions pivotally supported upon a pivot pin 31 situated in a lower portion of said chamber l8 and mounted in the body member to extend transversely thereof in parallel relation to the pivotal supports 2| and 25 for the thumb l6 and the fingers IT.

The actuating lever 35 consists of an elongated, inverted U-shape upper member 38 and a block shape lower member 39. The U-shape upper member 38 includes an upper'base 40 and spaced apart, parallel downwardly extending arms 4 4 I. The upper base 46 extends widthwise of the body member l5, and the spaced apart, parallel downwardly extending arms 4|, 4|. The upper base 46 extends widthwise of the body member I5, and the spaced apart, parallel arms 4|, 4| extend in the direction of the thickness of said body member. The block shape lower member 39 is rigidly secured to and situated between lower portions of the spaced apart, parallel arms 4| 4| and extends downwardly and rearwardly, and an end portion of said block shape lower member 39 is supported upon said pivot pin 37. The actuated lever 36 is of U-shape. It includes a base 42 and spaced apart, parallel, forwardly extending side portions 43, 43. The base '42 and spaced apart, parallel side portions 43, 43

of said actuated lever extend in the direction of the thickness of the body member l5 in a plane disposed perpendicularly to and longitudinally of said body member and including the actuating lever 35. A downwardly projecting ear 44 on each side portion 43, spaced apart a distance a trifle greater than a measurement representing the width of the block shape member 39, are situated at the corresponding side of a lower portion of said member 39 and said projecting ears are supported upon the pivot pin 31.

Intermediate parts of the spaced apart, parallel, forwardly extending side portions 43, 43, in spaced relation to the pivot pin 37, support a pivot pin 45 which extends widthwise of the body member IS in parallel relation to said pivot pin 31, and said pivot pin 45 in turn rotatably supports the forward ends of the links 22 and 21, respectively. Said links 22 and 2'? are at the outer sides of the spaced apart arms 4|, 4| of the upper member 38 of the actuating lever 35 and also at the outer sides of the side portions 43, 43 of the actuated lever 36 desirably in proximate relation to said side portions 43, 43.

A flat L-shape spring 46, having one of its end portions secured, as at 4?, to the block shape lower member 39 of the actuating lever 35 and its other end portion engaged, as at 46, against a lower portion of the base 42 of the actuated lever 36, has potential to normally urge said actuating and actuated levers apart, as in Figs. 2, 3, 4 and 5 of the drawings.

An operating entity or cord 49 for the actuating lever 35, secured, as at 56, to the upper base 46, extends rearwardly of the body member [5 and out of said body member through a slot 5|. The actuating lever 35 is adapted to be swung rearwardly, against resilient action of the flat L-shape spring 46, in response to manually accomplished rearward pulls upon the operating entity or cord 49, and said fiat L-shape spring is adapted to return said actuating lever 35 to its farthermost forward position, against a transverse stop 52 upon the body member I5, when said operating entity or cord 49 is released.

The compression coil spring 33, which normally urges the fingers l! to open position, also normally urges the actuated lever 36 to its farthermost forward position, which is about as disclosed in Fig. 8 of the drawings, through the instru- .mentality of the link 21 connected between said fingers I! and said actuated lever 36. In turn, the thumb I6 is normally urged to open position through the instrumentality of the link 22 connected between the actuated lever 36 and said thumb.

Each time the actuating lever 35 is swung rearwardly, in response to rearward pulling of the operating entity or cord 49, the actuated lever 36 is caused to be swung rearwardly. More explicitly, the rearward edges of the spaced apart arms 4|, 4| of the actuating lever 35 become engaged against the forward edges of the spaced apart side portions 43, 43 of the actuated lever 36 when said actuating lever 35 is swung rearwardly thus to cause said actuated lever to be swung rearwardly. When the actuated lever 36 is moved rearwardly, against resilient action of the compression coil spring 33, the thumb l6 and fingers H are caused to be moved toward closed condition through the medium of the links 22 and 21, and when said actuated lever 36 is released, said compression coil spring 33 of course will react to cause said thumb and fingers to be moved to their completely open condition.

Devices of the artificial hand adapted to be actuated, in response to a manipulation of the actuating and actuated levers 35 and 36 causing said thumb I6 and fingers I! to be moved from ing longitudinally of the body member.

open tc partially or completely closed condition; to cause the thumbq-and fingers to be positivelylockedin anynon-open condition .to which moved by saidlactuating and actuated levers; and to be actuated,- in response toa manipulation of the actuating and actuated levers next succeeding'a manipulation of said actuating and actuated levers which caused said: thumb and fingers to be moved from open to partially or completely closed condition, to cause the thumb and fingers to be released, thus to permit thecompression coil spring 33 to move said thumb and fingers to open condition, include an arcuate locking bar 53; a locking lever- 54., andan actuator element 55f0'r said locking lever. i Themearward end of the-arcuate lockingvbar -53-is pivotally supported on a cross pin 56 carried by the body member I5 and said arcuate locking bar extends upwardly and forwardly of said bodymember within its chamber I8 in direction longitudinally of the body member and in the vertical plane ofthe'actuating and actuated'levers 35 and 36. The forward'end of said arcuatelocking bar supportsa transverse stop 5:1situated-a trifle rearwardly of upper portions of the-spaced apart arms 4l', 4| of the'upper member 38-of' theactuating lever35 when in its far-thermost forward position and ashort distance downwardly of" the upper base 40 of said upperimember ofsaid actuating lever 35. The construction andarrangement will be such that when the actuating-lever 35 is swung rearwardly, the spaced apart arms 4|, 4| will be moved rearwardly-along opposite sides of the arcuate look.- ing bar 53 adjacent opposite ends of the transverse stop 51,: in clearing relation to said arcuate locking bar and transverse stop. r

The locking lever 54 is constituted as a block of 'rigid material which extends in the direction 'ofthe thickness of the body member l5 and is arranged in a plane passed longitudinally through ,said body member and including the arcuate locking bar 53 and the actuating and actuated levers 555 and 35 A lower end'portion of the lookinglever or block of material 54 is snugly situated between upstanding ears 53, 58 upon the upper-ends of the spaced apart side portions 43,

tear the actuated lever 35 and is mounted upon ap'ivct pin 59 supported in said upstanding cars 58'; 58 for swinging movement in a plane extend- A rectilinear slot 60 through an upper portion of said locking lever or block'of material 54, above the pivot pink e; is for passageof the arcuate looking bar 53, and the length of said rectilinear slot is substantially equal to a measurement representing' the thickness of said arcuate locking bar. The upper end of-the rectilinear slot 60 is defined by a knife edge 6| at an intermediate portion of the locking lever 54 and extending widths wise of the body member |5,va flat surface 62 extending forwardly from the knife edge 6 [in perpendicular relation to said locking lever and a flat surface 63 extending rearwardly and upwardly from said knife edge 6| inioblique relationtothe locking lever. The lower end ofysaid rectilinear slot 60 is defined by a knife edge 64 at an intermediate portion of said locking lever 54 and extending widthwise of said body member I5, a fiat surface 65extending rearwardly from the knife edge 54- in perpendicularrelation to the locking lever and a flat surface 65 extendingiforin, oblique relation to said locking lever. The, flat surfaces 62;.andg65are in parallehplanesh as are r 6 also the-flat surfaces 63'and 5B. The constru'd tion and arrangement will be such that the locking lever 54 selectively. can be situated radially, or approximately radially, of the arcuate locking bar 53, thus to cause the knife edges 6| and 64 to be free for sliding movement of said locking 7 lever along the arcuate upper andlower surfaces or edges of. said arcuate locking bar, and can be situated obliquely of the arcuate locking bar to cause said knife edges GI and '64 to be bindingly engaged againstv said arcuate upper and lower surfaces or edges of the arcuate locking bar, thus to preclude sliding movement of the locking lever relative to said arcuate locking'bar.

The actuator element 55 for the locking lever 54 is constituted as an oscillatablerectilinear element 6?, situatedv between the spaced apart arms 4|, 4| of the upper member 38 of the actuating lever 35, having its forward end ar ranged upon a pivot pin 58 mounted in forward intermediate portionsof said spaced apart arms 4|, 4| and supporting a working device 59 at its rearward end. A curled spring is on thepivot pin 68, having one of its end portions engaged against the rectilinear element 6! and its other end portion engaged against the block shape lower member 39, normally resiliently retains said actuator element 55 down against interiorly projecting stops 1|, 1| supported on said spaced apart arms 4|, 4| at the side of said rectilinear element 61 adjacent said lower member 39, and when the rectilinear element 61 is retained against the stops 1|, 1|, the actuator element 55. lies in a plane passed substantially perpendicularly and transversely through the upper member 38. The working device 69 is constituted as an elongated strip of rigid material, in alined relation with said rectilinear element 51 and loosely situated between the spacedapart arms 4|, 4|, fixedly supported upon guide rods 12; 12 slidably situated in longitudi nally extending guideways 13, 13. in the-roan Ward end portion of the rectilinear elemental Ajsmall compression coil spring 14 in a pocket 15; in saidzrearward end portion of said rectilinear. element: 5.1, betweenthe guideways l3,

13, normally urges the working device or elongated strip 5% to its farthermost position from said rectilinear element 5.1, and heads", 15 upon the inner'endscf the guide rods '62,;1'2 limit the; extent to which said working device or elongated strip 59 can be moved in direction away from the rectilinear element 61. The constructionv and arrangement will be such that theworking'device 69 will project slightly rearwardly of the rearward edges. of the spaced apart arms 4|, 4| when said working device is at, its farthermost position from said rectilinear element 52; about as disclosed in Figs. 2, 4 and 8 of. the drawings. A rearward surface or edge IT-of the/working device t9 extends widthwise of the body member I5, and the lower side of said rearward; surface Or edge 11 is bounded bya knife edgel'ii arranged inparallelrelationto the pivot pin 3.1.

A lower portion; of the locking lever 54 in,-

V cludes a first workingsurface 15 at the forward .wardly and downwardly from said knife edge 64 side of said locking lever and at about the elevationqof the pivot pin 59 adaptedto be engaged by-the-rearward surfaceror edge ,11 of the work: ing device 69 toucause the portion of the looking lever having the rectilinear slot t5; above said pivot ping59 to beheld in rearwardly tilted position; a second working surface 8;}; atv the forward ;si de; of said locking leverand ,at;eleva.-

tion below the pivot pin 59 adapted to be engaged by the rearward surface or edge ll of said locking lever and at elevation below the pivot pin 53 adapted to be engaged by the rear- Ward surface or edge if of said working device 69'to cause said portion of the locking lever above said pivot pin 55 to be rocked forwardly, and a fiat surface 8| between the first and second working surfaces l9 and 55 over which the knife edge 18 bounding the lower side of said rearward surface or edge 77 is adapted to be slidable in upward direction.

Sliding movement in forward direction of the lockinglever 54 on the arcuate locking bar 53 is adapted to be limited by engagement of an upper portion of said locking lever with the transverse stop 51, and oppositely disposed slots 82, 82 in the upper and lower surfaces of said arcuate locking bar 53 at a location adjacent the transverse stop 51 are for permitting free rocking movement of the upper portion of the locking lever 54 when the knife edges 6! and 64 are situated in alined relation with said slots.

The operative elements of the actuating mechanism of the artificial hand are situated, when the thumb l6 and the fingers H are in completely open position, so that the actuating lever 35 is engaged against the transverse stop 52, the locking lever 54 is in oblique relation to the arcuate locking bar 53 with the upper portion of the locking lever engaged against the transverse stop i, the rearward surface or edge 11 of the working device 65 is engaged against the first working surface 79 of said locking lever 54, and the small compression coil spring 74 is in substantially non-collapsed condition.

The operating entity or cord 49 is pulled rearwardly when it is desired to cause the thumb and fingers to be moved to partially or completely closed condition. The spaced apart arms 4|, 4| of the upper member 38 of the actuating lever 35 are swung rearwardly in response to pulling said operating entity or cord 49 rearwardly. The working device 69 is urged into engagement with the first working surface 19 to cause the small compression coil sprin 14 to be collapsed and the rearward edges of said spaced apart arm 4|, 4! engage the forward edges of the side portions 43, 43 of the actuated lever 36 upon rearward swinging movement of the spaced apart arms 4|, 4! to cause said actuated lever 36 to be swung rearwardly. The thumb l6 and fingers H are moved toward closed condition, through the medium of the links 22 and 2! and against the potential of the compression coil spring 33, in response to rearward swinging of the actuated lever 36. The actuator element 55 and the locking lever 54 of course are moved rearwardly with the actuating and actuated levers, and during its rearward movement said locking lever 54 is slid rearwardly along the arcuate locking bar 53. The working device 69 engages against the first working surface 19 during rearward movement of the actuating and actuated levers and causes the upper portion of the locking lever 54 to be held swung rearwardly. It will be apparent that any tendency which the upper and lower knife edges 6| and 64, at the ends of the rectilinear slot 60, might have to become bound against the upper and lower surfaces of the arcuate locking bar 53 while the actuated lever 36 is being swung rearwardly will be overcome or removed by reason of collapse to necessary extent of the small compression coil spring 14. That is, any tendency of the locking lever 54 toward becoming frictionally held against the upper and lower surfaces of the arcuate locking bar 53 during rearward swinging movement of said locking lever will be overcome or removed by collapse of the small compression coil spring 74 permitting the upper portion of the locking lever to swing forwardly toward radial relation to said arcuate locking bar.

, Upon release of the operating entity or cord 49 after it has been pulled rearwardly, the flat L- shape spring 45 will cause the actuating lever 35 to be moved to its farthermost forward position, against the transverse stop 52.

Immediately upon commencement of movement of the spaced apart arms 4|, 4| of the upper member 38 of said actuating lever 35 from a rearward position toward their farthermost forward position directly after said spaced apart arms and the actuated lever 36 have caused the thumb l6 and the fingers I! to be moved to partially or completely closed position, the compression coil spring 33 will start its reaction to have tendency to cause the links 22 and 21 to be moved forwardly and said actuated lever 36 to be swung forwardly upon the pivot pin 31. Evidently, forward swinging movement of the actuated lever 36 by reason of potential exerted by the compression coil spring 33 will create a tendency toward movement of the pivot pin 59, rotatably supporting the locking lever 54, forwardly thus to cause the lower end portion of said locking lever to be moved forwardly before the upper end portion of the locking lever upon the arcuate locking bar 53 has tendency to be moved forwardly. And, too, as long as the actuated lever 36 is engaged against the actuating lever 35, during initial movement of said spaced apart arms 4|, 4! forwardly, the working device 69 will retain the locking lever 54 tilted rearwardly by reason of engagement of said working device with the first working surface 19. Forward movement of the pivot pin 59 and the lower end portion of the locking lever 54 to a limited extent obviously will situate said locking lever at an oblique angle to the arcuate locking bar 53 adapted to cause the knife edges 6| and 64 to be bound against the upper and lower surfaces of said arcuate locking bar, about as disclosed in Fig. 4 of the drawings. Thus, the thumb I6 and the fingers I: when caused to be moved from open to partially or completely closed condition in response to a rearward manipulation of the actuating and actuated levers 35 and 36 will become locked in the partially or completely closed condition to which moved upon release of the actuating lever 35 for movement to its farthermost forward position.

Upon forward movement of the actuating lever 35 from a rearward position which caused the thumb l6 and the fingers ll to be moved to partially or completely closed condition and there locked, the rearward edges of the spaced apart arms 4| 4| will first become removed from the forward edges of the side portions 43, 43, and thereafter the working device 69 of the actuator element 55 will be moved forwardly to position where clear of the first working surf-ace 19. The curled spring 10, assisted by gravity, will act to move said actuator element 55 downwardly into engagement with the stops H, H upon movement of said workin device 69 to position where clear of said first working surface 19.

Assuming the parts of th artificial hand to be situated as in Fig. 4 of the drawings, where said parts are disclosed as when the locking lever 54 is fast upon the arcuate locking bar 53 and the actuating lever 35 is at its farthermost forward position, and said actuating lever; to be swung rearwardly-in response to rearward pulling of the operating entity or cord 49, the working device 69 will; firstiengag the. second. working, surface 3-0, and thereafter the small spring 14 will. become compressed and the rearward edges of the spaced apart arms, 4|, 4| will become engaged with the forward edges of the side portions 43, 43. Upon commencementof movement rearwardly of the actuated lever'fifi, after engagement of the spaced apart arms 4|, 4| with theside portions 43, 43 and by reason ofrearward movement of the actuating lever 35, the lower portion of the locking lever 54 will be. swung. rearwardly to cause or have tendency toward causing the upper portion of saidlecking lever to be swungr or rocked forwardly toward released relation to the arcuate locking ba'ra'nd thus assist the working device 69., byreason of the resilient action of, thesmall compression coil spring 14,, to situate the locking lever in substantially "radial relation to said arcuate. locking bar.,. See Fig. '7. Upon release ofithe operatingentity or cord 49, which canbe accomplishedsmoothly and gradually, to permit the spaced apart arms-4|, 4| of the actuating lever,35 to return to. their farthermost forward position," the actuated lever 36, together with the locking. lever '54 as a unit, will be returned to. its-farthermost forward position, in response t'oaction. offthecompression coil spring 33, while said locking lever is retained in substantially radial, relation-to and the knife dges 6|" and 64 are, held, clear. of the. arcuate locking bar 53 through theinstrumentality of the actuator element-55,. V

As hereinbefore stated, sliding movement in forward direction of the locking lever 54 is arrested by engagement of an upper portion of said locking lever with the transverse stop51 situated a trifle rearwardly of. the upper portions of the spacedapart arms 4|, 4| when in their farthermost forward position, and the slots 82, 8.2 in theupperandlower surfaces of the arcuate locking, bar 53 adjacent said transverse, stop 5'|.per-, mit-free rocking, movement in a rearward direction of the upper portion and in aforward direction: of the lowerportion, of the locking lever 54 when. the knife edges. G l-and 6,4 are situated in alined relation with, said slots.

Theconstruction. and arrangement will be such that the f-arthermost forward position for the actuating, lever 35 is somewhat. forwardly of the.

cause the lower portion of the locking lever to be swung forwardly and upwardly and the upper portion of said lockinglever to be swung rearwardly, thus to cause the locking lever to be situated in oblique relation, asin Fig. 8 of the drawings, to said arcuate locking bar. Forward movement of the. actuated" lever is arrested by engagement of 't'heupper portion of the locking.

lever 54:'with the" transverse stop 5'land of the knife: edges; 6| and64- with the upper and-lower surfaces of the arcuate locking bar 53. in response togforward; swinging movement of said actuated lever accomplished by thepotential of. SQJ-QMQQmr':

pression coil spring 33.

The actuated lever 36 when released from the arcuate locking bar- 53 moves forwardly with. and in following relation to the actuating lever 35 until said actuated lever has reached its farthermost forward position. Thereafter, said actuating lever 35- moves forwardly to its farthermost forward position and causes the working device 69 to be moved forwardly relative to the locking lever 54. The lower portion of said locking lever is swung forwardly and upwardly before the with drawal movement of said working device, and. forward, upward swingingmovement of said lower portion of the locking lever, in cooperationwith the potential of the small compression coil spring] 14, causes the working device 69. to be moved upwardly to and past alined relation with the.

pivot pins 68 and 59 from its position of engagement with the second working surface 89. to its position of. engagement with the first working surface 19. The upward movement of said working device is accomplished with a snap action, and during upward, movement the knife edge 78 of the working device slides over the fiat surface 8|. The working device 69 will become engaged with the first working surfacef|9 at about the sametirne. the actuating lever 35 has reached its farthermost forward position, and the operative elements of the artificial hand will be situated ready to be again manipulable in the manner as set forth when said working device is engaged with said first working surface and said actuating lever is at its farthermost forward position In Fig. 8 of the drawings the actuating lever 35 is disclosed in its farthermost forwardposi-- tion and the working device 69. is shown as when. being moved in snap action fashion upwardly from the second working surface 80 to the first working surface 19, and in Fig. 9 the actuating and actuated levers are disclosed as when being,

pulled rearwardly.

What isclaimed is 1. An artificial hand comprising resilient means urging a finger of said artificial hand toward open condition, a first lever adapted to be actuated against potential of said resilient meansto cause said finger to be moved to non-open condition and to be subjected when in said nonopen condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first'lever, and devices adapted. to be actuated by said resilient means upon release of the second lever from the first lever to cause the finger to be positively locked in any non-open condition to which moved by the first lever and to be actuated by the Second lever tocause the finger to be released from locked condition, said devices including a locking lever r0- tatably supported by said first lever and'having a rectinlinear slot, a pivotally supported arcuate locking bar in said rectilinear slot slidably receiving said locking lever, and an actuato element upon said second lever and supporting a working device, said locking lever including a first working surface adapted to be engaged by said workin device to cause the locking lever to be tilted in one direction when said first lever;

is actuated by said second lever against potential of said resilient means to cause said finger to be moved to non-open condition and a second Working surface adapted to be engaged by said working device to cause said locking lever to be rotated in an opposite direction when said first lever is actuated by said second lever to cause said finger to be released from locked condition.

2. An artificial hand comprising resilient means urging a finger of said artificial hand toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said nonopen condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever to cause the finger to be positively locked in any non-open condition to which moved by the first lever and to be actuated by the second lever to cause the finger to be released from locked condition to be capable of returning to open condition, said devices including a locking lever rotatably supported by said first lever and having a rectilinear slot, a pivotally supported arcuate lockin bar in said rectilinear slot slidably receivin said locking lever, an actuator element upon said second lever and supporting a working device, said locking lever including a first working surface adapted to be engaged by said working device to cause the locking lever to be tilted rearwardly when said first lever is actuated by said second lever against potential of aid resilient means to cause said finger to be moved to non-open condition and a second working surface adapted to be engaged by said working device to cause said locking lever to be rotated'forwardly when said first lever is actuated by said second lever to cause said finger to be released from locked condition and retained in forwardly rotated position while the finger is bein returned to open condition by potential of said resilient means, and means for causing said working device to become removed from said second working surface and engaged with said first working surface upon return of said finger to open condition.

3. In an artificial hand including a finger, resilient mean urging said finger toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said non-open condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever to cause the finger to be locked in any non-open condition to which moved by the first lever and to be actuated by the second lever to cause the finger to be released from locked condition, said devices including a locking lever rotatably supported by said first lever, a pivotally supported arcuate locking bar slidably receivin said locking lever, and an actuator element upon said second lever, said locking lever including a first working surface adapted to be engaged by said actuator element to cause the locking lever to be tilted in one direction when said first lever is actuated by said second lever against potential of said resilient means to cause said finger to be moved to non-open condition and a second working surface adapted to be engaged by said actuator element to cause said lockin lever to be rotated in an opposite direction when said first lever is actuated by said second lever to cause said finger to be released from locked condition.

4. In an artificial hand including a finger, resilient means urging said finger toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said non-open condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever after a manipulation of said second lever causing said first lever to move said finger from open to non-open condition to cause the finger to be locked in any non-open condition to which moved by the first lever and to be actuated by the second lever in response to a manipulation of said second lever next succeeding a manipulation of the second lever which caused said first lever to move said finger from open to non-open condition to cause the finger to be released from locked condition, said devices including a locking lever rotatably supported by said first lever, a pivotally supported arcuate locking bar slidably receiving said locking lever, and an actuator element upon said second lever, said locking lever including a first working surface adapted to be engaged by said actuator element to cause the locking lever to be tilted in one direction when said first lever is actuated by said second lever against potential of said resilient means to cause said finger to be moved to nonopen condition and a second working surface adapted to be engaged by said actuator element to cause said locking lever to be rotated in an opposite direction when said first lever is actuated by said second lever to cause said finger to be released from locked condition.

5. In an artificial hand including a finger, resilient means urging said finger toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said non-open condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever to cause the finger to be locked in any non-open condition to which moved by the first lever and to be actuated by the second lever to cause the finger to be released from locked condition, said devices including a locking lever rotatably supported by said first lever, a pivotally supported arcuate locking bar slidably and rockingly receiving said locking lever, and an actuator element upon said second lever, said locking lever including a first working surface adapted to be engaged by said actuator element to cause the locking lever to be tilted in one direction relative to said locking bar when said first lever is actuated by said second lever against potential of said resilient means to cause said finger to be moved to non-open condition and a second working surface adapted to be engaged by said actuator element to cause said locking lever to be rotated in an opposite direction relative to the locking bar when said first lever is actuated by said second lever to cause adapted to engage said second working surface upon said locking lever to retain said finger in released condition while the finger is being returned from non-open to open condition.

7. In an artificial hand including a finger, resilient means urging said finger toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said non-open condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, a pull cord for accomplishing manual actuation of said second lever adapted to be manipulated upon release of said finger from locked condition to cause the finger to be returned from non-open to open condition under the control of the second lever and the potential of said resilient means, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever after a manipulation of said second lever causing said first lever to move said finger from open to nonopen condition to cause the finger to be locked in any non-open condition to which moved by the first lever and to be actuated by the second lever in response to a manipulation of said second lever next succeeding a manipulation of the second lever which caused said first lever to move said finger from open to non-open condition to cause the finger to be released from locked condition, said devices including a locking lever rotatably supported by said first lever, a pivotally supported arcuate locking bar slidably receiving said locking lever, and an actuator element upon said second lever, said locking lever including a first working surface adapted to be engaged by said actuator element to cause the locking lever to be and remain tilted in one direction While said first lever is being actuated by said second lever against potential of said resilient means to cause said finger to be moved to non-open condition and a second working surface adapted to be engaged by said actuator ele-' ment to cause said locking lever to be tilted in an opposite direction when said first lever is actuated by said second lever to cause said finger to be released from locked condition and to remain tilted in said opposite direction while said pull cord is being manipulated to cause the finger to be returned from non-open to open condition.

8. The combination as specified in claim '7 wherein said locking bar rockingly receives said locking lever.

9. The combination as specified in claim 7 wherein one end portion of said locking bar is pivotally supportedand the opposite end portion of the locking bar is free for swinging movement.

10. The combination as specified in claim 7, and means for causing said actuator element to become removed from said second working surface and engaged with said first working surface upon return of said finger to open condition.

11. In an artificial hand including a finger,

resilient means urging said finger toward open condition, a first lever adapted to be actuated against potential of said resilient means to cause said finger to be moved to non-open condition and to be subjected when in said non-open condition to said potential of said resilient means, a second lever adapted to be actuated to cause said first lever to be actuated and to be released from the first lever upon completion of actuation of said first lever, and devices adapted to be actuated by said resilient means upon release of the second lever from the first lever to cause the finger to be locked in any non-open condition to which moved by the first lever and to be actuated by the second lever to cause the finger to be released from locked condition to be capable of returning to open condition, said devices including a locking lever rotatably supported by said first lever, a pivotally supported arcuate locking bar slidably receiving said locking lever, and an locking lever including a first working surface adapted to be engaged by said actuator element to cause the locking lever to be tilted rearwardly.

when said first lever is actuated by said second lever against potential of said resilient means to cause said finger to be moved to non-open condition and a second working surface adapted to be engaged by said actuator element to cause said locking lever to be rotated forwardly when said first lever is actuated by said second lever to cause said finger to be released from locked condition and retained in forwardly rotated position while the finger is being returned to open condition by potential of said resilient means.

12. The combination as specified in claim 11, and means for causing said actuator element to become removed from said second working surface upon return of said finger to open condition.

13. The combination as specified in claim 11, and a pull cord for accomplishing manual actuation of said second lever adapted to be manipulated upon release of said finger from locked condition to cause the finger to be returned. from non-open to open condition under the control of the second lever.

BERTIL G. PETERSON. ANNAR F. SYVERU'D.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,253,823 Hobbs Jan. 15, 1918 1,422,468 Nicola July 11, 1922 FOREIGN PATENTS Number Country Date 828,272 France Feb. 7, 1938 

